Structures and photochemical reactions of 1-(9-anthryl)-2-aroylethylenes: competing <i>cis</i>–<i>trans</i> isomerization and skeletal rearrangement
作者:Y. Mori、K. Maeda
DOI:10.1107/s0108768193008961
日期:1994.2.1
(Z)-3-(9-Anthryl)-1-phenylpropenone, cis-(I), C23-H16O, M(r) = 308.38, orthorhombic, P2(1)2(1)2(1), a = 14.992 (3), b = 19.124 (4), c = 5.614 (1) angstrom, V = 1609.4 (6) angstrom3, Z = 4, D(x) = 1.273 g cm-3, mu = 0.071 mm-1, F(000) = 648, R = 0.061 for 1101 observed reflections; (Z)-2-(9-anthrylmethylene)-1-indanone, cis-(III), C24H16O, M(r) = 320.40, monoclinic, P2(1)/a, a = 11.641(5), b=13.914 (10), c = 10.399 (6) angstrom, beta = 102.71 (4)degrees, V = 1643.1 (16) angstrom3, Z = 4, D(x) = 1.295 g cm-3, a = 0.072 mm-1, F(000) = 672, R = 0.060 for 2321 observed reflections; (Z)-2-(9-anthrylmethylene)-1-tetralone, cis-(IV), C25H18O, M(r) = 334.39, monoclinic, P2(1)/c, a = 9.106 (4), b = 25.977 (9), c = 7.478 (2) angstrom, beta = 96.76 (5)degrees, V = 1756.6 (11) angstrom3, Z = 4 D(x) = 1.264 g cm-3, mu = 0.070 mm-1, F(000) = 704, R = 0.070 for 1594 observed reflections; (E)-2-(9-anthrylmethylene)-1-tetralone, trans-(IV), C25H18O, M(r) = 334.39, monoclinic, P2(1)/c, a = 12.032 (2), b = 13.608 (3), c = 10.829 (3) angstrom, beta = 95.78 (2)degrees, V = 1764.1 (7) angstrom3, Z = 4, D(x) = 1.259 g cm-3, mu = 0.070 mm-1, F(000) = 704, R = 0.055 for 1985 observed reflections. cis-(I), cis-(III) and cis-(IV) exist in a conformation similar to each other, in which the anthracene plane forms a large dihedral angle [75.5 (3), 64.5 (1) and 67.2 (2)degrees, respectively] with the ethylene plane. These compounds rapidly undergo photochemical cis-trans isomerization in solution, while irradiation of cis-(I) in the solid state almost exclusively afforded an intramolecular [4+2] cyclization product, suggesting that the isomerization would be inhibited by crystal-lattice constraints. cis-(IV) also underwent [4+2] cyclization in the solid state, while in the case of cis-(III) only cis-trans isomerization was observed both in solution and in the solid state. A comparison of the molecular structures of cis-(I), -(III) and -(IV) suggested that the C(6)...O distance, where a new bond would be formed in the cyclization process, should be related to the photochemical reactivity.